The present invention relates to electrical devices and more specifically to switching devices which use a ground plate.
In conventional switching devices of the prior art, a ground plate is used for electrically grounding to provide an intentional path for current to ground. These plates also function to support various electrical components such as the switch and various terminals. These components are usually supported on a pair of rails which are fixed to the bottom of the ground plate. The rails are conventionally mounted on a separate plate which in turn is affixed to the bottom of the ground plate.
The above structure requires a separate rail assembly which is mounted to the bottom of the ground plate by spot welds, screws and the like. This structure requires a separate support rail component and the manufacturing steps associated with the assembling of the switching device. It can be seen that the support rail structure described herein is a separate component which adds to the cost of the switching device through added material costs, and separate manufacturing and assembly steps.
These ground plates also conventionally include a plurality of annular openings which accommodate the entry of suitable electrical cables into the electrical switching device. These openings usually contain an annular concentric knockout section, usually of reduced wall thickness, which allows the annular opening to be enlarged to accommodate a second or larger diameter cable and/or fitting. In removing or punching out the annular knockout, the force required to remove the knockout commonly results in bending the metal area surrounding the annular opening and damaging the integrity of the ground plate.
It can therefore be seen that there is a need for a knockout structure which effectively functions to enlarge the annular cable opening of a ground plate without damaging the integrity and operation of the ground plate.
It is therefore an objective of the present invention to provide a ground plate which overcomes the problems of the prior art described above.
It is another objective of the present invention to provide a ground plate having an integral support structure which allows for less material and assembly costs.
It is yet another object of the present invention to provide a ground plate for an electrical switching device which contains a support member which is an integral part of the ground plate.
It is a further object of the present invention to provide a ground plate for an electrical device which includes a pair of support members which are integrally formed as part of the ground plate.
The present invention is directed to a ground plate for an electrical device, such as a safety switch or the like, in which a pair of support rails are integrally formed as part of the ground plate.
More specifically the ground plate is in the form of a substantially flat base section which includes a pair of oppositely disposed vertical end members integral with the base section. The ground plate further includes a pair of support rails positioned perpendicular to the base section between said end members. The support rails are formed integrally as part of the base section through cuts through the thickness of said base section at predetermined locations. The cut sections are then bent at a right angle to form the rails.
The ground plate of the present invention is a one piece unitized device which requires less material and less assembly time (cost) than the composite ground plates of the prior art, while being functionally equivalent, and in some cases functionally better than the conventional ground plates described herein.